THE EXPERIMENTAL STUDY OF HYDRONEPHROSIS BY ELECTRON MICROSCOPY

Abstract

Ligation of the rat (Wistar) ureter was done for 1, 2, 3 days and 1 week in order to produce hydronephroais. After nephrectomy, papilla, fornix, brown pelvis and white pelvis were fixed by 2% glutaraldehyde solution (Millonig buffer pH 7.2). Then each specimen was dehydrated through a graded ethanol, which was replaced in isoamyl acetate. They were critical point dried, coated with gold and observed by scanning electron microscope.
The results of the observation were as follows.
1) Rats have unipapilla, and their pelvis could be separated macroscopically into those with brown and those with white pelvis.
2) Enlargement of the orifice of the papillary duct began to be observed after 24-hour hydronephrosis, and became more evident as time passed.
3) Increase of microvilli on the papillary epithelium was observed as the hydronephrosis advanced. In 1-week hydronephrosis, fusing of microvilli was observed.
4) From the brown pelvis of 24-hour hydronephrosis rat, epithelial waving was observed, which suggested a tubular structure formed under the mucosa.
5) On the cell surface of the brown pelvis, microridge concentration toward the center of the cell was observed in a reticular and radial formation in accordance with the advance of hydronephrosis, and a microcrater was observed in the center.
6) On the cell surface of white pelvis were seen rippling folds focussing on the center of the cell, forming a microcrater as if it were a volcano.
7) There was no tendency to separation or scaling-off of cells, nor was forniceal rupture observed.
It was concluded that the urinary absorption in hydronephrotic rats occurs mainly through pyelotubular backflow.